In article ,
OM om@our_blessed_lady_mary_of_the_holy_NASA_researc h_facility.org wrote:
http://www.meccano.us/differential_a..._da/index.html

Not, of course, a new idea... The second differential analyzer in the
world was Hartree and Porter's 1934 Meccano design -- although they
cheated by using some non-Meccano parts -- which was built purely as a
model of the larger machine they planned next, but to everyone's surprise
turned out to be accurate to 1-2% and quite useful for problems where that
was adequate.

(Several laboratories had started construction of differential analyzers
in imitation of the original at MIT, but H&P's Meccano model was finished
first because it was so cheap and needed so few custom-made parts.)
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |